TZ History Every time zone change, ever made, explained

Etc/GMT

Time zone identifier: Etc/GMT

Current civil offset: +00:00 (UTC)

Current DST state: Observing Standard Time

First standard time adoption: Not recorded

Total recorded transitions: 0 transitions across 0 distinct offsets

Aliases (Link targets): Etc/GMT+0, Etc/GMT-0, Etc/GMT0, Etc/Greenwich, GMT, GMT+0, GMT-0, GMT0, Greenwich

Advertisement Space

Historical Offset Step Chart (1880 to Present)

-5:00 -4:00 -3:00 -2:00 -1:00 +0:00 +1:00 +2:00 +3:00 +4:00 +5:00 1880 1900 1920 1940 1960 1980 2000 2020

Text summary: Etc/GMT shifted between 0 distinct offsets from standard time introduction through the modern era.

Complete Transition History (0 Transitions)

No historical transitions recorded for this zone.

Notes from the Maintainers

Source: etcetera (Lines 22 to 27) 
If leap second support is enabled, functions like gmtime
load the "GMT" file to handle leap seconds properly.
Vanguard section, which works with most .zi parsers.
Zone	GMT		0	-	GMT
Rearguard section, for TZUpdater 2.3.2 and earlier.

Methodology Note: The 1970 Rule

tzdb guarantees accuracy for timestamps from 1970 onwards. Transitions prior to 1970 represent best-effort historical reconstructions.